Difference Analysis on Meteorological Response Factors of Potential
Evapotranspiration on Different Time Scales---Taking Beijing Station as
The response of meteorological elements to potential
evapotranspiration(ET0) varies greatly from different time-scale
perspectives, but current research are mainly focused on a certain
time-scale and lack the study on the response of various meteorological
elements to ET0 variations based on different time-scale perspectives.
This situation results in the unilateral perception of variations in ET0
caused by climate change. Therefore, this study qualitatively explore
the sensitive factors of ET0 on different time scales by sensitivity
coefficients, and quantitatively characterize the actual contribution
amounts of major meteorological elements to variations in ET0 on
different time scales by contribution rate combining the sensitivity
coefficients with the relative variation rates of meteorological
elements. Results are listed as follows. (1) The SRH is always negative,
but SRn, ST and SU are positive. The main sensitivity factors of ET0
vary on different time scales. Specifically, RH and Rn become the major
sensitive factors alternately within a year. On an interannual basis,
the Rn was the most sensitive factor from 1958 to 1963, and the most
sensitive factor became RH from 1964 to 1978. RH and Rn became the most
sensitive factors to ET0 alternately from 1979 to 2017. (2) The
contributions of each meteorological element fluctuate significantly. On
the daily time scale, the GT and GU are large at the beginning and end
of the year. The GRn and GRH are dominant in the middle of the year. On
the monthly and seasonal time scales, RH contributes the most in spring
and autumn and Rn does in summer. The GT and GU are dominant in winter.
On the yearly and multi-yearly time scales, the main contributing
factors are RH and T. In summary, the increase in ET0 in Beijing area is
mainly caused by the decrease in RH and the increase in T. The decreases
in U and Rn also slow down the further increase in ET0 in this area.
This blocking effect caused by Rn in summer is highly evident.